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Moving a pendulum

  1. Feb 25, 2009 #1
    I'm doing some computer graphics and I'm pretty new to physics/mechanics. Right now I'm simulating a pendulum. But now I want to be able to move the pendulum to, the point to which the string is connected (for instance if I hold the pendulum between my fingers and move my hand). Now which forces are acting on the pendulum now, how can I update it's position? I'm simulating everything with a computer, so I want the movements to be arbitrary.
  2. jcsd
  3. Feb 25, 2009 #2


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    Welcome to Physics Forums.

    That all depends on the constraints placed on the motion of the pivot. If the pivot is contained to moved with a constant velocity, then the transformation is straight forward. If the pivot is accelerating at a constant rate, then the transformation is still fairly straightforward. If however, the pivot is allowed to accelerate arbitrarily then things could become a little more involved.
  4. Feb 25, 2009 #3
    Thanks! Well actually I want to be able to move the pivot around with the mouse..any hints?
  5. Feb 25, 2009 #4
    You might want to look into the Lagrangian formalism. It makes these sorts of things a lot easier, and it is especially apt to producing good things for computer simulations.

    Using it requires some calculus, but that should be expected.
  6. Feb 26, 2009 #5
    Thanks, any good links? Calculus is no problem...
    Actually I don't need to get too much and deep information, this is just something I do for fun as a graphical effect
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